Alternative protein encapsulation with MOFs: overcoming the elusive mineralization of HKUST-1 in water.

Protein encapsulation by in situ formation of MOFs is a valuable strategy to immobilise and protect these bioentities. However the required biocompatible conditions limits the scope of MOFs under investigation, particularly in the case of hydrolytically unstable MOFs such as HKUST-1. We report alternative synthetic procedures to obtain protein@HKUST-1 biocomposites from related Cu-BTC dense biocomposites. pH dependent dense phase precursors are first obtained and their transformations into HKUST-1 are characterized. Encapsulation efficiency is affected by the protein's nature, and can be modulated by the sequential or simultaneous addition of MOF precursors.

Exploiting the Redox Activity of MIL-100(Fe) Carrier Enables Prolonged Carvacrol Antimicrobial Activity.

The design of efficient food contact materials that maintain optimal levels of food safety is of paramount relevance to reduce the increasing number of foodborne illnesses. In this work, we develop a smart composite metal-organic framework (MOF)-based material that fosters a unique prolonged antibacterial activity. The composite is obtained by entrapping a natural food preserving molecule, carvacrol, into a mesoporous MIL-100(Fe) material following a direct and biocompatible impregnation method, and obtaining particularly high payloads. By exploiting the intrinsic redox nature of the MIL-100(Fe) material, it is possible to achieve a prolonged activity against Escherichia coli and Listeria innocua due to a triggered two-step carvacrol release from films containing the carvacrol@MOF composite. Essentially, it was discovered that based on the underlying chemical interaction between MIL-100(Fe) and carvacrol, it is possible to undergo a reversible charge-transfer process between the metallic MOF counterpart and carvacrol upon certain chemical stimuli. During this process, the preferred carvacrol binding site was monitored by infrared, Mössbauer, and electron paramagnetic resonance spectroscopies, and the results are supported by theoretical calculations.